| Patent application number | Description | Published |
|---|
| 20100067018 | Phase Based Sensing - Interrogation of a phase based transducer is performed by comparing the state of the transducer at two points in time to determine the rate of change with time of the measurand represented as a phase change. The rate of change, or derivative of the phase change typically has a much smaller amplitude than the signal itself, and the derivative measurement can therefore be thought of as a low sensitivity measurement to be used instead of or in combination with the normal signal measurement having higher sensitivity. In this way, large amplitude signals which might otherwise be subject to overscaling effects can be measured more effectively. For a signal with the majority of its energy centred at approximately 800 Hz, for example, the derivative of that signal will typically be attenuated by 60 dB with a period between the two measurement times of 200 ns. | 03-18-2010 |
| 20100098114 | Frequency Control Method and Apparatus - A feedback control circuit and method for controlling laser frequency employing an interferometric phase sensor which accepts a light output from a laser and combines a phase modulated version of the light output, with an unmodulated version. By modulating only one component of the signal in the interferometric sensor, the improved noise characteristics are obtained, while demodulation can be performed relatively easily and cheaply. Methods and enclosures for reducing ambient noise in an interferometer or the delay coil thereof are also described. | 04-22-2010 |
| 20100177302 | Phase Based Sensing - A method of interrogating a phase based transducer by providing a pulsed input including two different wavelengths. The different wavelength components can be used to derive a phase change experienced by a synthetic wavelength, and by arranging for the synthetic wavelength to be significantly greater that the component wavelengths, the phase so detected has a reduced sensitivity, and is less susceptible to overscaling effects. | 07-15-2010 |
